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Maxim > Design Support > Technical Documents > Application Notes > Amplifier and Comparator Circuits > APP 1949
Maxim > Design Support > Technical Documents > Application Notes > Automotive > APP 1949
Maxim > Design Support > Technical Documents > Application Notes > Battery Management > APP 1949
Keywords: bidirectional, current sense amp, current monitor, battery, charge current, discharge current,
amplifier, amplifiers, amps
APPLICATION NOTE 1949
Bi-directional Current-Sense with Single Output
By: Franco Contadini
Mar 25, 2003
Abstract: Battery operated devices often need to monitor both charge and discharge currents. A dual
current-sense amplifier and differential amplifier are combined to produce a single output voltage that
indicates magnitude and direction of battery current.
Systems such as laptop computers and other devices that have internal charge circuitry require a precise
bi-directional current-sense amplifier to monitor accurately the battery's current regardless of polarity.
The MAX4377 (a dual low-cost current-sense) can be used to produce a bi-directional current monitor.
Figure 1.
Output voltage OUT_ is proportional to the magnitude of the sense voltage (V
RS
+ - V
RS
-).
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